Thread: Checking for spark

Had a good look at the ute yesterday. It has the sparkplugs with the coil pack on top of each sparkplug. So the spark plug leads are just two wires disappearing into a loom. How do you time these engines?

As it happens it is the fuel pump. I went into Holden and they gave me a printout of the page of their manual and it states that the pressure should be 43 to 55 psi (296 to 376 kpa). The pump was nowhere near this. In fact the last time we checked it the pump didn't pump at all! I have since removed the pump from the tank and connected it to a battery. It draws current and sometimes it spins but is having a hard time of it. Other times it tries to spin but can't. I am trying to get the thing apart as Holden priced a new one at $800!!! Surely there is just a blockage in there (the pickup is about 3mm from the bottom of the tank).
The Holden dealer also mentioned they had sold 4 in the last 12 months. Three were pump failures and the 4th a sender failure (they're an all in one unit).

I've posted it in the Outer Limits Isuzu section but if anyone here has any idea on how to get the frigging pump apart I'm all ears.

Just an Aside, or is it back to topic ...
On real cars with carbon graphite leads coming from a single induction coil, you can quite often see the 'spark' travelling through the lead insulation in the very very very dark.
Looks kinda freaky seeing the ignition alive like this.


Ralph

Well I stripped the pump down and pulled the motor completely apart. I found nothing wrong with the motor other than the brushes were wearing the copper contacts instead of the other way around. So I put it back together partially and powered it up and it ran fine. So I put it back together and once again it ran fine. So today I put it back into the tank (after a throrough cleaning) and the car started first go. So we bolted the tank back in and took it for a test drive and there were no problems.
So if this doesn't last (and who really knows when you fix something that was never meant to even come apart) I'll fit an external pump. I've priced some that should suit for $200.

Thanks for the help.

get a replacement holden one from supercheap.. they only run about $85 but check your manual for the required flow rates and pressure, make sure the new pump isnt too far off that.

Originally Posted by Blknight.aus

get a replacement holden one from supercheap.. they only run about $85 but check your manual for the required flow rates and pressure, make sure the new pump isnt too far off that.

The replacement Bosch and Walbro ones I looked at had pressures of 3 bar and 5 bar. 3 bar is about 43.5 psi which is at the bottom end of the 43-55psi range for the Rodeo. 5 bar is way off the scale at around 75psi. They came in various flow rates. I don't know the flow rate of the Rodeo pump though.

you may find that 75psi is the stall rating of the pump, and its a cleverway of getting more money for a cheapy pump...

the pump should have a graph with it that concerns itself with pressure vs flow..

as flow increases pressure should decrease.. and vice versa.. some pumps have multiple taps to them (adjusted before you put it in its housing) but these are aftermarket jobbies and I dont trust them much.

You may find that your 75psi pump may be the go for your donk if youve got multi point injection as these have flow when running and check valves to prevent overpressure, when the overpressure valve cracks the pump will restart and just keep pumping while the valve stays open. (once the engine is running but that varies from manufacturer)

Have a good look at the fuel flow schematic and see whats what and where.

you could also work out the flow rate of the pump by disconnecting the return line from the pressure regulator and routing that into a graduated container, time it for 15 seconds and multiply out for LPM's or run it for a minute and see what you get.